1181091 has 4 divisors (see below), whose sum is σ = 1574792. Its totient is φ = 787392.

The previous prime is 1181057. The next prime is 1181093. The reversal of 1181091 is 1901811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1901811 = 3 ⋅633937.

It is not a de Polignac number, because 1181091 - 2¹⁸ = 918947 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1181093) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 196846 + ... + 196851.

It is an arithmetic number, because the mean of its divisors is an integer number (393698).

2^1181091 is an apocalyptic number.

1181091 is a deficient number, since it is larger than the sum of its proper divisors (393701).

1181091 is an equidigital number, since it uses as much as digits as its factorization.

1181091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393700.

The product of its (nonzero) digits is 72, while the sum is 21.

The square root of 1181091 is about 1086.7801065533. The cubic root of 1181091 is about 105.7047378242.

The spelling of 1181091 in words is "one million, one hundred eighty-one thousand, ninety-one".